Sludge treatment faceing the following problems:
1. dry sludge generally contains 65% of the organic matter and 35% of the inorganic. In China, the content of organic matter in sludge is low.
2. wet sludge contains a wide variety of bacteria, viruses and parasites, bacteria in which a large number of breeding.
3 .sludge also contains zinc, copper, lead and cadmium and other heavy metal compounds, toxic organic compounds, pesticides and so on, all of which once entered the food chain will lead to serious health problems. This problem is particularly prominent in large and medium sized cities in the industry.
In Europe, according to the provisions of the European Union: by the end of 2015, the organic matter content of more than 5% of the waste landfill will be banned; in the United States, according to the provisions of the State Environmental Protection Administration of sludge health law, only after the treatment of sterilization, to bacteria or virus can not be detected by the class a sludge can sell in the market; and the use of class B sludge must meet the special conditions of use, namely sludge bacteria or virus content not to the public and the environment impact. The special grade sludge, the sludge of bacteria or viruses and heavy metals content to meet the requirements, the use of the same as the limit of the use of fertilizers. Because a grade a sludge has no restrictions on the content of heavy metals, so the State Environmental Protection Administration of the 503 sludge health law is not very strict. At present, in the state of New Jersey, in California, Nevada and Arizona, part of the county legislation has been enacted prohibition of sludge landfill; Florida and some state legislation is underway.